Hi Keith. Welcome.
When I started my orchard, I inquired about peach planting density. I really didn’t get a solid answer. That’s because some growers seem to make any density work. Even peach guru Jerry Frecon gave me this answer, “I could take you to orchards with 16’ row spacing. When trees are heavily laden with fruit, you can hardly walk down the rows. I see the growers drive equipment through these blocks and break limbs, knock off and bruise fruit but he does not worry about it because he says he is picking up to
1200 bushels per acre at this close spacing and high vigor.”
I don’t know what a modified open center pruning method is, but you will definitely have a lot of pruning to do with high density planting.
I ended up using a low density planting (about 100 trees per acre) and I’m glad I did. I had previous experience in my one acre yard that mature peach trees 20’ apart would give little room to drive between them with a riding mower.
I knew I would have to make room for larger equipment with a commercial orchard, so I ended up spacing my trees 18’ apart in the row, and 25’ between rows. I’ll admit the 25’ between rows is a wide spacing for most commercial peach orchards, but even at this we still have to keep an eye on the pruning to make sure the trees don’t creep into the rows too far, else the equipment will knock fruit off. At 18’ apart in the rows, we have to cut the trees back, so they don’t grow into each other. I will mention, peach trees here tend to be very vigorous, in this soil, so it’s hard to keep them contained.
Quite a few people on this forum use much tighter spacing than that. The problem translating that to a commercial orchard, is that home growers don’t count their labor, because it’s a labor of love.
In commercial orchards, labor is a big deal, so you’ll want to try to minimize it. You won’t have time to “fuss” over your trees all summer, so ease of pruning becomes paramount. High density peach systems work, but are not conducive to easy pruning.
Part of the problem is that peaches, in an open vase system, naturally have the most productive fruiting zone toward the outside, or upwards (if you let them). It’s generally not practical to let a peach tree grow upwards, so the alternative is outside.
Trying to keep the tree somewhat constrained from growing outward makes it hard to keep those outward zones productive as the tree matures. It’s a lot of pruning just to keep the trees at pedestrian height (which is paramount, imo - especially so for a Upick orchard) it’s even more difficult to try to keep them contained within a tight horizontal area, at the same time. It can be done, it’s just harder.
Your trees may not be as vigorous in NC, so it may not be as big of an issue there.
Here is what Desmond Layne (respected guru) has to say about it:
https://www.clemson.edu/extension/peach/commercial/breeding/tree-density-and-profitability.html
I’d see how vigorous your trees are in your soil. If you have problems with overcrowding in your first planting, I’d recommend cutting every other tree out, so the spacing is 16’ or 20’ between trees. They do this with pecan orchards. Plant to twice the recommended planting density, then come in after so many years and thin the orchard to the recommended density.
